Choose appropriate chemical composition analyzer
In order to refine and homogenize the graphite structure, the first step is to select the appropriate proportioning scheme for medium frequency furnace bar year, especially the way of carburizing. At the same time, the parameters such as smelting temperature, inoculation treatment process, initial temperature of cylinder mold and pouring temperature should be strictly controlled, and the cooling conditions of different crystallization temperature periods should be controlled to obtain graphite metallographic structure in accordance with the standard.
Select the appropriate chemical composition and use the way of carburizing agent. According to the production practice and the introduction of relevant data, the carbon equivalent of large and medium-sized cylinder liners is generally controlled between 3.6-4.0. Carbon and silicon strongly promote graphitization, and the high C and Si content will lead to coarse graphite. In order to obtain the ash mouth, the content of C and Si should be properly reduced in a certain range, which is conducive to refining graphite. Meanwhile, the content of alloy elements should be strictly controlled, which can not only refine graphite but also effectively prevent segregation.
By changing the way of carburizing, increasing the proportion of scrap steel and reducing the proportion of pig iron, the carburizing agent was used. Reducing the amount of pig iron can reduce the carbon clusters in molten iron after melting, which in essence slows down the tendency of forming coarse graphite in Eutectic Transformation and greatly reduces the bad genetic effect of pig iron. This process enables the castings to obtain high strength under the condition of high carbon equivalent, and greatly improves the casting process of medium frequency furnace melting large and medium-sized marine cylinder liners.
For the control of sulfur content, there is no sulfur source in the process of medium frequency furnace melting cast iron, and the s content of molten iron is low. In the later stage of smelting, the s content is increased to 0.06% ~ 0.1% by adjusting the composition and adding FES. When the content of s in hot metal is high, with the increase of Mn content, MNS is suspended in the molten iron to form heterogeneous crystalline core, which can effectively improve the inoculation effect and obtain fine and uniform A-type graphite. The pearlite lamellae in the matrix is refined and the hardened phase is evenly distributed, so as to improve the strength of cast iron and improve the machinability.
Nanjing Nuojin high speed analysis instrument factory specializes in producing high frequency infrared carbon and sulfur analyzer, which can effectively detect the content of carbon and sulfur in cast iron materials.
Nanjing Nuojin high speed analytical instrument factory
October 9, 2017
- 上一篇:Determination of element conte 2017/10/13
- 下一篇:Nanjing Nuojin high speed anal 2017/9/26